Electrolytic experimental set up
The schematic arrangement of the experimental setup is shown in Fig. 1. The experiments were carried out in a cylindrical reactor having a capacity of 5 L. Al and Fe electrode plates in two combinations (Al–Fe and Fe–Al) having different surface areas (40, 80, 120 and 160 cm2) were connected to the respective anode and cathode leading to the DC rectifier and energized for a required duration of time at a fixed voltage. The inter-electrode distances between the two neighboring electrode plates varied between 2.5 and 10 cm (Table 1). All the experiments were performed at room temperature (30 ± 2 °C) and at a constant stirring speed (100 rpm) to maintain the uniform mixing of effluent during the electrolytic procedure. Before conducting an experiment, the electrodes were washed with water, dipped in dilute hydrochloric acid (HCl, 5 % v/v) for 5 min, thoroughly washed with water and finally rinsed twice with distilled water. After electrolytic treatment, the effluent was allowed to stand for 2 h and then sampled for analysis.